A Wizard? a Mighty Valar? Eru himself? No one quite knows what he is but--

Hey! Ho! Merry dol! It's Tom Bombadilo!

Probably my favorite Tolkien Character; he appeared in many video games but never in a film adaptation. He had power over almost everything using song, but only in the boundaries he set for himself. Things happening in the wide world had little to no hold on his mind which is why he was rejected as an alternative to destroying the Ring. He helped the Four Hobbits out of the Old Man Willow and invited them to his house where they stayed for two nights. He later saved them from the Barrow-Downs and gave them their swords. He is only ever mentioned again as Gandalf is going to visit him.